BIG GUNS - Battleship Basics
Gun power exploded during the battleship period. A fire officer working with a battleship's battery of uniform caliber guns could calibrate their trajectory, time of flight and range for one devastating impact.
Before HMS Dreadnought, battleships had single guns of various calibers, meaning control over a gunfire pattern was diminished. The Dreadnought, commissioned in 1906, had ten 12-inch/45-caliber guns that could fire an eight-gun salvo of 850 lb. shells at a speed of 2,725 ft. per second with a range of 16,400 yards.
By World War II, the 12-inch gun was an anachronism. Japan's IJN Yamato, the biggest and most powerful battleship ever built, featured 18-inch/45-caliber guns that could fire 3,219 lb. shells at a speed of 2,559 ft./second at a range of 45,960 yards.
Battleships had also adopted a range of fast-firing, close-range anti-aircraft (AA) guns to defend against aircraft attacks. Many medium-range guns doubled as AA guns. The presence of AA guns by the end of World War II was essential to a ship's survival.
The USS Missouri, which served in the US Navy until the early 1990s, went a step further and added Tomahawk cruise missiles and high-tech anti-ship missiles to its battery.
TURRETS:
Revolving gun turrets made a battleship's big gun power possible.
With a gun turret, the entire ship did not need to turn to line up its guns; only its gun turret did. Gun turrets had first appeared in the mid-19th century, but, initially, their weight was too much for the ships that carried them. HMS Captain and USS Monitor both sank, pushed down by turrets that lowered their clearance with the waterline.
With the advent of high-strength steel, the 1906 HMS Dreadnought, the first modern battleship, could easily support turrets. Positioning varied - the US Navy favored the center of the ship, at staggered heights. The Royal Navy put the Dreadnought turrets in the ship's center and facing each other on either end of the ship. Early turrets moved via hydraulic power; World War II-era ships featured electric-powered turrets.
Protection for gun turrets was key: Adopted from the French, the barbette, a fixed, armored shield, protected the platform on which the guns stood, and let guns fire out of the top. With the increase of rapid, small-arms fire, this became impracticable, and the closed turret was readopted with the barbette guarding the turret's rotational mechanism, ammunition loading system, roller track, supports . Guns and crew were protected by a thick steel shield.
ARMOR:
Armor was essential to a battleship's survival.
Its placement was complex. Good armor must provide adequate protection without weighing down the ship and decreasing its speed.
Early versions of battleship armor featured wrought iron reinforced by oak panels or steel reinforced by wrought iron. With improvements in the quality of steel, big gun battleships became heavily coated in steel plates - sometimes as much as two feet thick. Ship designers aimed to provide sufficient protection to withstand guns as powerful as a ship's own.
The amount and placement of armor varied, but five locations were absolute musts: turrets, decks, barbettes, bulkhead (vertical parts of a ship's structure), belt (strip lining the bottom of the ship, partly under and partly over the waterline) and conning tower (command tower).
SPEED:
Without the turbine engine, battleships would never have reached the big gun status.
Sails and masts, as HMS Captain demonstrated, were incompatible with large, heavy gun turrets and weapons. Even with steam power, a ship's need to stay close to ports with coal supplies proved a serious disadvantage.
With the turbine engine, ships' power exploded. Though the source of energy has changed from electric batteries to nuclear power, turbine engines today remain the main method for powering modern navies.
The HMS Dreadnought in 1906 could travel at 21.4 knots with four turbine engines providing 23,000 shaft horsepower. Fewer than 40 years later, the USS Missouri, one of the last US battleships, could do 33 knots with steam turbines providing 212,000 shaft horsepower.
